Connector Fastener Sealing Against Electrolyte-Driven Galvanic Corrosion

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Solution Overview

Problem

In the automotive wire harness industry, dissimilar metals used in connectors and fasteners are prone to galvanic corrosion when exposed to electrolytes, leading to potential leaks and damage.

Innovation Solution

A non-conductive silicone seal is employed to protect areas where dissimilar metals come into contact, preventing the ingress of electrolytes and thus preventing galvanic corrosion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If dissimilar metals are used in connectors and fasteners, then electrical conductivity and mechanical strength are improved, but galvanic corrosion occurs when exposed to electrolytes

Engineering Contradiction:
Improvemechanical strengthVSAvoidresistance to galvanic corrosion
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

A non-conductive seal (EPDM rubber or silicone) is introduced as an intermediary material between dissimilar metals (e.g., aluminum connector housing and steel fastener). This seal prevents direct contact between the dissimilar metals, eliminating the galvanic corrosion pathway while allowing the fastener to secure the connector. The seal acts as a physical barrier that isolates the electrolyte from the metal-to-metal contact areas.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

A flexible non-conductive seal (EPDM rubber or silicone) is used to create a protective barrier around the fastener and between dissimilar metal surfaces. The seal deforms to accommodate the fastener geometry and maintains continuous protection against electrolyte ingress, preventing galvanic corrosion at the interface between dissimilar metals.

Inventive Principle:
Principle #30Flexible shells and thin films

2Reliability

If a seal is added to protect fasteners from electrolyte, then resistance to galvanic corrosion is improved, but device complexity increases

Engineering Contradiction:
Improveprotection from galvanic corrosionVSAvoidnumber of sealing components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The non-conductive seal serves multiple functions simultaneously: (1) it provides galvanic corrosion protection by isolating dissimilar metals, (2) it maintains the electrical insulation properties required for wire harness safety, and (3) it can contribute to the sealing of the connector housing. This multi-functionality reduces the need for additional separate protective components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The protective seal is integrated with the connector housing structure rather than being a separate fastener component. The EPDM or silicone seal is molded into the housing or applied as a continuous barrier that combines structural support with corrosion protection, eliminating the need for separate protective sleeves or coatings.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The silicone seal effectively prevents galvanic corrosion in areas between dissimilar metals, ensuring the integrity and longevity of the connector devices by isolating them from electrolytes.

Implementation Method 1

when two or more dissimilar metals come into contact in an electrolyte, one acts as an anode and the other acts as a cathode. The presence of an electrolyte, which provides an electrical conducting path between dissimilar metals, causes galvanic corrosion to occur

Methodology Applied
Scientific EffectGalvanic corrosion:

Implementation Method 2

The presence of an electrolyte, which provides an electrical conducting path between dissimilar metals, causes galvanic corrosion to occur

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3833880B1System and method for sealing a metal fastener from electrolyte in an area of dissimilar metals
Publication Date: 2024.01.17 JST CORP
  • EP3833880B1 patent drawingFigure 1
  • EP3833880B1 patent drawingFigure 2

AI summary

A sealing system and a method for sealing a metal fastener and members having dissimilar metals for a header connector or a connector device from electrolyte in an area where, in the header connector or the connector device, certain dissimilar metals may be in contact. The metal fastener and other adjoining or abutting dissimilar metals are sealed by a non-conductive seal from electrolyte, thereby protecting the metal fastener and the other adjoining or abutting dissimilar metals from galvanic corrosion and subsequently protecting the integrity of the header connector or the connector device.